Method of making elastic yarn



Aug 13g 1940 F. DfcHrrTENDEN r-:r A1. 2,210,884

METHOD OF MAKING ELASTIC YARN BY l A'rroRNEYs Aug.13,194o. FgD.CHITTENDEN UAL 2,210,884 Y METHOD oF MAKING ELAsTIc YARN Filed Fei. 11,1959 2 sheets-sheet 2 VIV/A Patented Aug. 13, 1946 UNITED vSTATES PATENTOFFICEy Rupprecht,

Barrington,

R.. I., assignors to United States Rubber Company, New York, N. Y., acorporation of New Jersey Application February 11, 1939, Serial No.255,912

8 Claims.

This invention relates to improvements in the method of and apparatusfor making a balanced .elastic yarn consisting of a twisted rubber corehaving a single cover of textile fibers spun about the core in adirection to cause the helical windings of the cover to balance thetwists of the rubber core,

In making such an elastic yarn it is necessary first to twist the barerubber core, after which the cover is spun thereupon in the oppositedirection. Approximately fty per cent of the twist imparted to the barerubber core is or may be removed as the cover and core are spun togetherto wind the cover about the core. Therefore it is necessary to impart arelatively high number of twists per inch to the rubber core preparatoryto spinning the cover thereupon, and the cost of pretwisting this rubbercore unless performed at high speed and under the most favorableconditions may constitute a substantial part of the cost of producingsuch elastic yarn.

The elastic yarn above described and one method of making the same isfully disclosed and claimed in the Boutwell H. Foster Patent No.2,024,156 granted December 17, 1935. But in this, Foster patent the barerubber core is described as having been previously twisted and woundonto' a spool from which it is supplied to the mechanism for spinning acover thereupon.

One important feature of the present invention resides in the method ofan apparatus for -pre twisting the bare rubber core and then spinningthe cover thereupon vall in a continuous operation.

In order that the nished elastic yarn herein contemplated may be wellbalanced and uniform in construction and stretch characteristics it isimportant to avoid the occurrence of variations in the stretch of therubber core at certain stages during the formation of the elastic yarn.This is particularly true with respect to the operation of pretwistingthe rubber core, because variations in the stretch of the rubber core atthis time will change greatly the number of twists per inch impartedthereto.

Another important feature of the invention therefore resides in feedmeans for drawing the rubber thread endwise from the rotating let-offpackage at a definite speed to thereby impart tol this thread apredetermined number of twists per inch for a given percentage ofstretch, and a further feature resides'in the construction whereby theoperation of this feed means at a definite speed ratio to the nip rollsof the spinning mechanisms to which the rubber thread is deliveredserves accurately to control the tension of this thread at the instantit is being delivered to the thread, which is rotated as the thread isdrawnv endwise therefrom to twist the thread, may be supported invarious positions as the thread is drawn therefrom. For example it iscontemf plated that the thread may be drawn downwardfrom the package inthe direction of gravity, or:

upwardly therefrom against the force of gravity, or at angles to thesepositions.

One of the more speciiic features of the invention therefore resides inthe arrangement whereby the rubber thread travels in a general downwarddirection from the time it leaves-the rotating supply package until thecover is spun thereupon and the yarn is wound on the take-up package. 4l

Other features of the invention and novel combination of parts inaddition to the above will be hereinafter described in connection withthe accompanying drawings which illustrate good practical forms of theinvention.

In the drawings:

Fig. 1 is a conventional diagrammatic view with parts in section of oneform of mechanism for carrying out the invention;

Fig. 2 is an enlarged side view of an elastic yarn formed upon theapparatus of Fig. 1 and comprising an elastic core and a cover woundhelically thereupon;

Fig. 3 is a top view of the motor brake mechanism of Fig. 1;

Fig, 4 is a view similar to Fig. 1 showing a modific-ation thereof; and

Fig. 5 is a similar view showing a further modiiication of Fig. 1. Thepresent invention was developed primarily for the manufacture of fineelastic yarns having a core as fine as 75s or finer, although theinvention may be employed to manufacture elastic` yarns having a largercore. A large number of twists per inch must therefore be imparted tothis ne rubber thread before the cover is spun thereupon, and the numberof twists may be as high as 200 per inch or higher. It is thereforeimportant that the mechanism provided to impart this twist to the nevrubber thread shall operate at high speed in order to give a reasonablyhigh production of elastic yarn per covering unit 'I'he bare elasticthread l0 forming the core of the elastic yarn may be formed of rubberor-other rubberlike material having the desired stretch characteristics.This thread which is to be twisted, or what'may be called pre-twisted,is preferably wound on a relatively small spool II so that the packagesthus formed my be rotated at a speed of say 10,000 R. P. M. or higher.The rubber thread I0 is wound upon this spool in an untwisted conditionand under sufficient tension to prevent the entire mass of rubber on thespool from ballooning or bulging outwardly under the high centrifugalforce caused by the rapid rotation of the spool. The bare rubber threadI0 is twisted in accordance with the present invention by rotating thespool or package I I about its longitudinal axis and by drawing thethread endwise therefrom over one head.

In Fig. 1 the rubber thread I0 is shown as drawn downwardly from thesupply spool I I in an axial direction. In the modification of Fig. 4 itis shown as drawn upwardly from the spool I I in an axial direction, andin the modification of Fig. 5 the thread I0 is shown as drawnhorizontally from the spool II in an axial direction.

Referring first to the embodiment of the invention shown in Fig. 1, itwill be vnoted that the arrangement is such that the package II extendsdownwardly from its rotating means so that the thread may be drawndownwardly therefrom. By employing this arrangement the force of gravityis utilized to help advance the thread in a general downward directionfrom the spool to the spinning mechanism to be described.

The spool II is shown as mounted upon the spindle I2 and the spool maybe frictlonally secured to this spindle or may be held in placethereupon by the cap I3. The spindle I2 may, if desired, be driven by abelt but is shown as driven by a small high speed electric motor I4which motor may be secured to any suitable supporting means such as thesupporting rail I5.

It is important, as above stated, to draw the thread I0 from the spoolat a'uniform speed so that the twist per inch imparted to this threadwill be as near uniform as possible. Therefore in the embodiment of theinvention shown in Fig. 1, feed means is provided below the rotatingspindle I2 for pulling this thread downwardly at a definitepredetermined speed. This means comprises a feed roll I6 which may bedriven at any desired speed by the gear I1, vand the rubber thread I0 isheld in feeding engagement with this roll by the idler roll I8 which isrotatably supported between the spaced arms I3 of a swinging bracketthat is pivotally mounted at I9' upon a support 20. 'I'he arrangement issuch that the idler I8 rests by gravity upon the feed roll I6 and thisidler may be swung upwardly away from the roll I6 to facilitatethreading up of the device.

As the thread I Il unwinds from the rapidly rotating spool I I it willtend to balloon or swing outwardly as shown in Fig. 1. 'I'his isdesirable if not excessive, since it helps to get the thread away fromthe head of the spool, it also helps to take up slight variations in thetension of the thread as it unwinds from the spool. 'I'he size and shapeof this balloon may be controlled largely by the position at which thethread guide orpigtail 2I is located below the spindle I2 in axialalignment therewith. This pigtail is preferably pivotally secured to athread board 22 in a well known manner so that the pigtail may be swungupwardly out :of the way to permit the.

spool I I to be doffed. If desired the thread board 22 may be mountedfor vertical adjustment upon its support 20 to thereby move the pigtail2l toward or from the spool II, to control the ballooning of the threadI0.

The twisted, or pre-twisted thread I0 upon leaving the feed roll I6 mayhave a textile cover spun thereupon substantially as disclosed in theFoster patent above cited, and the spinning mechanism employed to spinthe twisted rubber thread and textile cover together to form the elasticyarn may be of the usual or well known construction. It is shown asprovided with roving drafting means and a ring and traveler although aflier type of spinning means may be used.

In the construction shown the spinning mechanism is provided with theusual pairs of drafting rolls 23, 24 and 2 5. The covering materialwhich is preferably a roving or rovings may be supplied to the draftingmechanism from the roving supply spindles 26. Two ends of roving 21 areshown as extending to the drafting rolls, as two ends will give a moreuniform product than a single end of roving. These rovings 21 passthrough the roving guide 28 supported by a bracket 29 which bracket inturn is secured to the traverse bar 30. This bar 30 as is usual is givena short traverse movement to advance the roving lengthwise of the feedrolls and thereby lessen the wear upon these rolls. It is desirable toimpart a similar traverse movement to the rubber thread I0 as it passesdownwardly to the nip of the drafting rolls 23 so as to 4bring theroving and rubber thread together at the nip of these rolls. This isreadily accomplished by providing a thread guide 3| upon the bracket 29to travel therewith and which is adapted to guide the rubber thread I0as it passes from the feed roll I6 to the nip of the rolls 23.

The spinning mechanism is shown as having the usual spinning spindle 32which is journaled in a bearing 33 mounted upon the fixed support 34 andthis spindle is shown as having the usual whirl that is driven by a belt35 from the rotating drum 36. Upon the spindle 32 is mounted a bobbin 31upon which the finished elastic yarn 38 is wound. The bobbin 31 as isusual rotates within an opening within the ring rail 39 which istraversed up and down in a well known manner to wind the yarn uniformlyupon the bobbin 31. 'I'he ring rail 39 is provided with the usual ring4I and traveler 4I. Above the upper end of the spindle 32 is providedthe thread guide or pigtail 42 carried by the thread lboard 43 andsecured thereto bythe usual hinge so that it may be thrown upwardly outof the way of the bobbin to facilitate doiiing.

It is found in practice that in order to produce a balanced elastic yarnthe number of windings in one direction of the covering material in oneinch of the relaxed elastic yarn should be approximately equal to thenumber of twists of the rubber core in the opposite direction in thisinch of elastic yarn. This, however, is only approximate and may varywith the size of rubber core used relative to the covering materialused. Therefore when the twists of the core approximately equal theopposite winding of the cover the lower spindle 32 will be operated atabout one-half of the speed of the upper spindle I2 but in the reverseddirection so as to remove during the spinning operation about one-halfof the twist which was previously imparted to the bare rubber core.

The take-up package 3B may 'be rotated in either a clockwisel orcontra-clockwise direction provided the let-off package II rotates inone direction and the take-up package 38 rotates in the oppositedirection. That is the package 33 should always be rotated in adirection to reduce the twist imparted to the rubber core by therotation of the spool I I.

Most of the spinning action which results in winding the textile coverabout 'the rubber thread as a core takes place adjacent the dischargeside of the ni-p rolls 23, and since the rubber core is stiffer and hasa greater contractive tendency than the drafted roving the core takesthe central position and the drafted fibers are wound thereabout as acover as clearly shown in Fig. 2.

It will lloe seen from Fig. I that by operating the feed roll I6 anddrafting rolls 23 at the proper speed relative to each other and to thelet-o and take-up packages, the amount of twist per inch imparted to thebare rubber thread and the tension of the rubber thread between the feedroll I6 and nip of the rolls 23 may be accurately controlled. Thisserves to provide the proper number of twists and the proper tension ofthe rubber core to form a balanced elastic yarn.

Since it is contemplated that the let-olf spool I I will be operated athigh speed it may be desirable to Aprovide manually controlled brakemeans to checkv rapidly the rotation of the spindle I2 after its drivingpower has been cut off. Therefore this spindle is shown as having abrake disc 44 about which is looped a brake band 45. One end of this4band is anchored to a fixed post 46 and the other 'end is connected bya spring to an, arm 41 that projects laterally from a shaft 48 rotatablymounted in a bearing 49 and adapted to be turned slightly about itslongitudinal axis to apply the brake.

While the construction shown in Fig. 1 has the motor I4 for twisting thethread I0 as it is .pulled .off one end ofthe spool II, it may bedesirable in some ,cases to operate the various parts of the machine ofthe presen-t invention from a single motor so as to correlate accuratelythe operating speed of the spool II, feed roll I6, drafting rolls, andspinning spindle 31. Therefore in the modied constructions of Figs. 4and 5, the spindle for supporting the let-oil' package II is shown asprovided with a driving whirl instead of the driving motor I4 .of Fig.1.

In the constructionA shown in Fig. 4 the spool II of rubber thread to betwisted is mounted upon the 4upper end of the vertical spindle 50. This,spindle is journaled in the supporting bracket 5I and may be driven bythe whirl 52. Above the spindle 50 is provided the pigtail guide 53similar to the guide 2I of Fig. 1. The rapid rotation of the spool IIcauses the thread I0 to balloon as shown, as it passes upwardly to thepigtail 53. It then passes upwardly from this pigtail to the idler roll54 and then downwardly between the feed roll 55 and cooperating idleroll 56 which may be similar in construction and operation to the rollsI6 and I8 of Fig. 1. From the roll 55 the twisted thread passesdownwardly to the drafting rolls 23 to meet the drafted roving 21 andcause this roving lto be spun about the thread I0 as a cover, 'the sameas in Fig. l.

It has been found in practice that while the construction of Fig. 1 hasthe desirable feature of utilizing gravity to facilitate the travel ofthe thread from the let-olf spool to the take-up package, it is open tothe objection that in some cases the outer coils tend to drop down overtheY head of the spool as its rotation is being stopped. I'he u'ptwisting construction of Fig. 4 avoids this tendency. l

In Fig. '5 the spool I I of rubber thread is mounted upon a horizontalspindle 51 having the opercolorating whirl 58, and the thread I0 uponleaving this spool passes through the guide 59 and then about anI idler60. From this idler it is pulled downwardly by the feed roll 6I andidler 62. From this point on the operation is the same as in Fig. 4.

In the construction shown in Figs. 4 and 5 it is contemplated that thelet-off and take-up spindles and various feed rolls will all be drivenfrom the same source of power so that the speed ratio between theseparts will remain constant.

It will be apparent from the foregoing that as a result of the apparatusand method of the present invention the rubber thread that is to formthe core of the elastic yarn is pre-twisted in one direction and is thensubjected to a spinning operation which removes part of this twist asthe covering material is spun thereuponin the opposite direction, and-that these operations are carried out simultaneously and continuouslyas the rubber thread travels from the let-off package II to the take-uppackage 38. l

In order that the elastic yarn herein contemplated may be furtherunderstood the following tables are given as illustrating a few of themany constructions that may be made by employing the method andapparatus of the present invention.

Tables of construction 1. Gauge of round rubber core, relaxed-- 125S 2.Elastic yarn, relaxed yards per lb.-- 11,000 3. Elongation or totalrange of stretch of the elastic yarn per cent-; 125 4. Material ofcover-2 ends 10 hank combed Sakellaridis roving 12 draft. 5. Length ofbare core in 1 yard of elastic yarn inches-- 26 6. Bare rubber core percent by weight 45 '1. Cover per cent by weight 55 8. Gauge, elasticyarn, relaxed inches .0105 9. Average strength of elastic yarn at breaklbs.-- 0.42

. Gauge of round rubber core, relaxed-- Elastic yarn, relaxed yards perlb. 6500 .y Elongation or total range of stretch of the elastic yarn percent-- 4. Material of cover-2 ends 5 hank combed-peeler roving 12 draft.5. Length of bare Acore in 1 yard, elastic yarn inches-- 25.5 6. Barerubber core per cent by weight-- 42 7. Cover per cent by weight 58 8.Gauge, elastic yarn, relaxed 0.0140 9. Average strength of elastic yarnat break` lbs. 0.55

III

1. Gauge of round rubber core, relaxed-- 75 2. Elastic yarn, relaxedyards per lb.-- 3700 v 3. Elongation or total range of stretch of theelastic yarn per cent-- 120 4. Material of cover- 2 ends 3 hankcombed-peeler roving 12 draft. 5. Length of bare core in 1 yard, elasticyarn inches-- 24.5 6. Bare rubber core per cent by weight-- 37 7. Coverper cent by weight-- 63 8. Gauge, elastic yarn, relaxed 0.020 9. Averagestrength of elastic yarn at break lbs.-- 1.09

While the covering for the elastic yarn shown in Fig. 2 is preferablyformed of a drafted roving or rovings, it is contemplated that themethod and apparatus of the present invention may be `employed to applya textile yarn or other form of strand about the rubber thread as acover. Through the present invention it is possible to produce anelastic yarn which is well balanced and in which the helical windings ofthe drafted roving blend together to form a soft smooth cover thatclosely resembles ordinary textile yarn in feel and appearance.

Having thus described our invention, what we claim and desire to protectby Letters Patent is:

1. The method of making a balanced elastic yarn having la twisted rubbercore and a textile cover spun thereupon, which consists lin rotating apackage of bare rubber thread and pulling the thread endwise therefromto twist it in one direction, and advancing this thread as it is twistedand a textile roving towards spinning means to thereby spin said rovingabout the core in the opposite direction so as to form a helical coverupon the core adapted to balance the twist of the core and hold itstretched.

2. The method of making an elastic yarn having a twisted rubber core anda cover spun thereupon in the opposite direction, which consists inrotating a package of rubber thread and pulling the thread endwisetherefrom to twist it in one direction, and advancing this thread as i'tis twisted and a covering strand towards spinning means to thereby spinsaid strand about the core in the opposite direction so as to wind itabout the core as a cover and reduce the twist of said core.

3. The method of making an elasticl yarn having a twisted rubber coreand a cover spun thereupon in the opposite direction, which consists inrotating a package of rubber thread andpulling the thread endwisetherefrom in a downward direction to twist it in one direction andadvance this thread in a downward direction as it is twisted towardsspinning means, feeding a covering strand also towards said spinningmeans to thereby spin this strand about the core in the oppositedirection to wind it about the core as a cover.

4. The method of making an elastic yarn having a twisted rubber coreanda cover spun thereupon in the opposite direction, which consists inrotating a package of rubber thread and pulling the thread endwisetherefrom to twist it in one direction, advancing the thread as it istwisted towards spinning means and simultaneously stretching it apredetermined amount, feeding a covering strand also towards saidspinning means to thereby spin this strand about the core in theopposite direction to wind it about the core as a cover.

5. I'he method of making an elastic yarn having a twisted rubber coreand a cover spun thereupon in the opposite direction, which consists inrotating a let-off package of rubber thread and pulling the threaddownwardly therefrom to twist the thread and utilize the force Aofgravity in removing the thread from said package, simultaneouslyrotating the take-up package of spinning means for this thread in adirection to reduce the twist of this thread as it is wound on saidtake-up package, and delivering a covering strand to said spinning meansso as to spin it about said thread as a cover.

6. 'I'he method of making an elastic yarn having a twisted rubber coreand a cover spun thereupon in the opposite direction, which consists inrotating a let-off package of rubber thread and pulling the threaddownwardly therefrom to twist the thread and utilize the force ofgravity in removing the thread from said package, simultaneouslyrotating the take-up package of spinning means for this thread in adirection to reduce the twist of this thread as it is wound on saidtake-up package, delivering acovering strand to said spinning means soas to spin it about said thread as a cover and controlling the stretchof said rubber thread as it is delivered to said spinning means.

7. The method of making an elastic yarn'having a twisted and tensionedrubber core and a cover spun thereupon, which consists in rotating apackage of rubber thread and pulling the thread endwise therefrom at auniform rate of speed to twist it in one direction, advancing thisthread as it is twisted at another point at a different uniform speed tothereby tension the thread a predetermined amount and feed it towardsspinning means, delivering a covering strand also towards said feedingmeans to thereby spin said strand about the core in the oppositedirection so as to wind it about the core as a cover.

8. The method of making an elastic yarn having a twisted rubber core anda cover of textile bers spun thereupon in the opposite direction, whichconsists in rotating a package of rubber thread and pulling the threadendwise therefrom in a downward direction to twist it, drafting unspuntextile fibers and advancing them towards spinning means, and advancingsaid thread as it is twisted towards said spinning means to thereby spinthe textile fibers about the core in an opposite direction to wind itthereupon as a cover.

FAYE'I'IE D. CHI'I'IENDEN. y KENNETH J. RUPPRECHT.

